27 Feb 2015
Whilst most alpine paleoclimate archives have been destroyed by Late Pleistocene glacier erosion, cave sediments, and in particular speleothems, may preserve information over hundreds of millennia. By analysing the stable isotope composition of accurately dated stalagmites from the Sieben Hengste cave system (Switzerland) the paper demonstrates that, in contrast to present days, a substantial amount of precipitation reached the study site from the South. This analysis supports an overall shift of the North-Atlantic storm track during the Last Glacial Maximum, forcing moisture from the warm subtropics towards the Alps. Enhanced precipitation combined with low temperatures favoured the build-up of large ice masses south of the main alpine crest 25 ka ago. These results suggest that seasonality may have been a dominant forcing for alpine glacier advances and thus, also controlling the Northern Hemisphere wind pattern. This work can serve as a benchmark for model simulations of past changes in the storm tracks delivering moisture to the Alps.
The publication is open-access and can be downloaded here.